Island



April 2,1929. J. B. OLCH LET-OFF DEVICE FOR LOOMS Filed March 12, 1928 llaco B 0% Patented Apr. 2, 1229.

JACOB B. OLCE, OF PROVIDENCE, RHODE ISLAND, ASSIGINOR TO CROMP'ION 8t KNO'WLES LOOlVI WORKS, OF WORCESTER, MASSACHUSETTS, A. CORPORATION OF MASSACHU- SETTS'.

LET-OFF DEVICE FOR LOOIEES.

Application filed. March 12, 1928.

This invention relates to let-offs for looms and it is the. general object of the invention to provide means for temporarily disabling the retarding device for warp beams to permit the weaver to turn the loom back more easily.

Certain let-offs are constructed with compound levers which are operatively related to a friction element such as a flexible strap which cooperates with the warp beam of the loom. After a pick-out has been made it is necessary to turn the beam backwardly to restore the fell of the cloth to the proper position and as there are ordinarily two friction elements, one at each end of the beam, it is desirable that one of them be temporarily disabled or rendered ineffectiveso that the two hands of the weaver 'may be freed to hold up the other retarding device andreverse the beam. It is an important object of my present invention to provide means for temporarily rendering the compound levers of the let-off mechanism inoperative so far as the tensioning of the warp is concerned by means which are supported entirely by the levers.

In one arrangement of compound levers which has gone into general use two levers are connected by a link, the arms of one lever being in a different ratio from the arms of the other lever, so that the two lovers have different angular movements although they are connected together. It is a further object of my present invention to employ in connection with such compound levers a link which will connect the two levers at points which normally move at different rates and to have the link of such length that it will hold the levers in fixed position with the friction element slack.

With these and other objects in view which will appear as the description proceeds, my invention resides in the comb-ination and arrangement of parts hereinafter described and set forth in the claims.

In the accompanying drawings, wherein I have shown a convenient embodiment of my invention, 7

Fig. 1 is a rear side elevation, port-ions be ing in section, of a let-off having my invention applied thereto and with the let'ofi in position to exert normal retarding force on the beam,

Fig. 2 is a view similar to Fig. 1 but with Serial No. 260,888.

the levers rendered temporarily inoperative to slacken the friction element, and

Fig. 8 is an enlarged vertical section on line 33 of Fig.2.

Referring particularly to Figs. 1 and 2 the loom frame 10 supports a warp beam 11 having a friction drum 12 around a portion of which is extended a flexible friction element 13. One end of said element is an chored to fixed structure as at 14 while the other end is connected as at 15 to the rear of an upper lever 16 pivoted as at 17 to the loom frame. The lever 16 has a forwardly extending arm 18 which by means of link 19 is pivotally connected to the relatively short arm 20 of a lower lever 21 pivoted as at 22 to the frame. The rearwardly extending arm 23 of the lower lever is notched as at and supports a weight IV in such a position as to exert force on the flexible element 13. Y

The upper lever may have the arms thereof substantially in equal ratio as shown, while the lower lever may have the arms in unequal ratio so that by means of link 19 the effect of weight W is considerably multiplied. The weight W exerts its pressure upwardly through link 19 to tend normally to lower the rear end of the upper lever 16 so as to hold the strap 13 tightly against the drum 12. lVhile I have shown the levers as moving in a plane pependicular to the axis of the beam yet I do not wish to be limited to this arrangement as it has been common practice heretofore to mount the levers so that they move in planes substantially parallel to the axis of the beam. The matter thus far described is of common construction and forms no part of my present invention, and it is to be understood that each end of the warp beam will be provided with a set of compound levers and associated parts. I

In carrying my invention into effect I provide the upper lever 16 shown in the drawings with an opening and form the corresponding lower lever with a corresponding opening 31 which is'preferably under the opening 30. The opening 30 is preferably at such a distance from the stud 17 that when the two levers are moved that part of the lever 16 having the opening 30 therein will move at a different rate of speed from that part of lever 21 in which opening 31 is located.

A connecting link 32 has a bearing arm 34 extending through the opening 31 and may have acotter pin 35 located so as to permit said link to move toward and from the lever 21 and still retain said link against accidental loss. The upper end of said link is provided with a second substantially horizontal arm 36 which may be conical as at 37 to facilitate entry into the upper opening 30.

Under normal conditions the link 32 will be in the position shown in Fig. 1, the cotter pin 35 holding the link against accidental loss. When in this position the weight lV is effective to operate in the ordinary way to tension the strap 13 and fl ereb'y retard movement of the warp beam 11. When it is desired for any reason to relieve the pressure exerted by flexible element 13 the link 32 will be swung upwardly and the tapered end 37 inserted into the hole 30. This latter operation cannot be accomplished except for one critical position of the two levers because of the fact that the openings and 31 move at different rates of speed. The lower lever will be raised until the end 37 can enter the opening 30, after which the link is moved to the position shown in Fig. 3. The link will thereafter operate to hold the two levers in the relative positions shown in Fig. 2 with the element 13 slack. The operators hands are then free to release the other friction device which will be at the opposite end of the loom and also to turn the beam backwardly. After the need for slack in the element 1?) no longer exists the link 32 will be moved to the right from the position shown in Fig. 3 and allowed to swing downwardly to the position shown in Fig. 1, after which the weight W will be effective to restore the original tension on the strap or element 13.

From the foregoing it will be seen that I have provided a very simple means for connecting together two levers of a compound system of leverage in such a position as will slacken the friction element so that the same will be ineffective to retard movement of the warp beam. It will further be seen that this result is achieved by a connection between the two lovers which is supported entirely by said levers. Also, it will be seen that the slackening of the element 13 as described is rendered possible by reason of the fact that the two parts of the levers which are connected together normally move at different rates when the levers swing about their respective centers, and that because of this fact a single element can hold the levers in locked position with the desired slack.

Having thus described my invention it will be apparent that changes and modifications may be made therein by those skilled in the art without departing from the spirit and scope of the invention and I do not wish to be limited to the details herein disclosed, but What I claim is:

1. In a let-off for a loom having a Warp beam and a friction element normally effective to retard movement of the beam, a system of compound levers one of which is weighted, said system being operatively connected to the friction element to retard movement of the beam, and a link effective to connect two of the lovers in a position torender the element ineffective to retard novement of the beam.

2. In a let-off for a loom having a warp beam, a friction element effective to retard movement of the beam, and a system of compound lcvers operatively connected to the friction element, means to connect one part of one of the levers with a part of another lever which moves at a different rate of speed from the rate of the first part mentioned when said levers move about their centers, said means effective to hold the levers in such a position as to render the friction clement ineffective to retard movement of the beam.

3. In a let-off for a loom having awarp beam, a friction element effective to retard movement of the beam, and a system of compound levers operatively connected to the friction element, pivots for the levers of the system so located that a portion of one lever will move at a different rate of speed from that at which an adjacent portion of another lever moves when said levers move about their pivots, and means to connect said portions to hold the friction element normally ineffective to retard movement of the beam.

4. In a let-off for a loom having a warp beam and a friction element normally effective to retard movement of the beam, a system of compound levers operatively connected to the friction element, said system including two levers which are operatively connected together, and means to connect together a portion of one lever with a portion of another lever which moves at a different rate of speed from the first named portion when. said levers move about their pivots to render the friction element ineffective to retard movement of the beam.

5. In a let-off for a loom ba ing a warp beam, a friction element effective to retard movement of the beam, and a system of compound levers operatively connected to the friction element, said system of lovers including an upper lover, a pivot for said upper lever, a lower lever, a pivot for said lower lever, a link connecting said levers, said link being connected to the levers at such distances from the respective pivots of the levers as to cause said levers to have different angular rates of movement when said levers move about their pivots, and means to connect said levers together in such a position as to render the friction element ineffective to retard movement of the beam.

6. In a let-off for a loom having a Warp beam a friction element eifective to retard movement of the beam, and a system of compound levers operativeiy connected to the friction element, said system including two levers connected together and moving at different angular rates about their axes, and means to connect said levers together in a 10 position to render the friction element ineffective to retard movement of the beam.

In testimony whereof I have hereunto afiixed my signature.

JACOB B. OLCH. 

